1. Field of the Invention
This invention relates to a catalyzed interfacial polycondensation aromatic polycarbonate process wherein the polycarbonate is formed in the aqueous phase in particulate form.
2. Description of the Prior Art
In general, interfacial polycondensation publications including "The Encyclopedia of Polymer Science, Vol. 10 (1969), "Chemistry and Physics of Polycarbonates, Polymer Reviews", H. Schnell, Vol. 9, John Wiley & Sons, Inc. (1964); "Polycarbonates", Christopher N. Fox, Rheinhold Corporation of New York, (1962); among other publications, including numerous and foreign patents, e.g., Great Britain No. 1,222,003, U.S. Pat. Nos. 3,227,681; 3,275,601; 3,318,845; 3,879,347; 3,879,348; 3,989,672; and West German Offenlegungsschrift No. 29 01 668, report generally effective interfacial polycondensation processes.
Heretofore, an interfacial polycarbonate process wherein (1) the initial two-phase reactant admixture contains a liquid inert organic solvent phase to a liquid aqueous phase--on a volume-volume (v/v) basis--range of from 0.04:1 to 0.20:1 during (2) the preparation of an aromatic polycarbonate having a weight-average molecular weight (M.sub.w) of at least about 2000 wherein the aromatic polycarbonate is formed in particulate form in the liquid aqueous phase has not been reported.
The benefits associated with the process include (1) the use of substantially reduced amounts of liquid phase inert organic solvent during the poly-condensation process, and (2) the elimination or reduced use of (i) anti-solvents in the separation and recovery of aromatic polycarbonate from the reaction environment, and/or (ii) steam precipitation techniques to recover any aromatic polycarbonate in solution in the organic phase--since substantially all of the polycarbonate formed precipitates in-situ in the aqueous phase in particulate form.